直肠癌是我国常见的消化道恶性肿瘤之一 ,其发病率有逐年上升趋势 ,但其根治性手术术后 5年生存率始终徘徊在 5 0 %左右。局部复发是死亡的主要原因 ,约 80 %的患者死于局部复发而无远处转移 ,80 %的局部复发发生在术后 2年内 ,低位直肠癌即病灶位于腹膜返折以下的复发率较高 , Rectal cancer is one of the most common malignant tumors of the digestive tract in our country. The incidence of rectal cancer has been increasing year by year. However, its 5-year survival rate after radical surgery has remained at about 50%. Local recurrence is the major cause of death, with about 80% of patients dying from local recurrence without distant metastases, and 80% of local recurrences occurring within 2 years after surgery. Low rectal cancer, ie, a lesion with a higher recurrence rate below the peritoneal fold ,